Add ForLoopsLowering to JVM phases.

Also deleted StepHandler. Since the HeaderInfo.needLastCalculation is
only set to true for handling step progressions, deleted that property
and all associated logic around it.

compiler/testData/codegen/bytecodeText/forLoop/forInRangeToLongConst.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 const val N = 42L
 
 fun test(): Long {

compiler/testData/codegen/bytecodeText/forLoop/forInRangeWithImplicitReceiver.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 fun Int.digitsUpto(end: Int): Int {
     var sum = 0
     for (i in rangeTo(end)) {

compiler/testData/codegen/bytecodeText/forLoop/primitiveLiteralRange1.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 fun f() {
     for (i in 1..2) {
     }

compiler/testData/codegen/bytecodeText/forLoop/primitiveLiteralRange2.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 fun f(a: Int, b: Int) {
     for (i in a..b) {
     }